Lakes

The morning of the day the Las Conchas fire started, the air was so hot, the soil so dry I went looking to see if any prickly pear were blooming anywhere this season.

One place I walked was an open field just beyond the near arroyo. Nothing. Not a flower, hardly a healthy plant in a place they bloom year after year.

The Pacheco fire was still burning towards Tesuque and was sometimes visible from the road in the area. I looked that way from somewhere in the center of the field and, besides smoke, saw something I’d never noticed before. The field looked like a great bay that water had washed over from a break in the badlands.

Saturday, when I was in the near arroyo, I wondered how it connected to that open space which it had to border somehow. The bed narrows between five or six foot walls a little beyond the point where water begins channeling itself for the culverts. As I went up stream from there, it turned to the left and suddenly opened into a great, wide expanse with almost no banks.

I remembered something similar in the far arroyo. Yesterday I walked back to refresh my memory. Again, the tall walls make a turn, this time to the right, and a great expanse opens.

I came home to pour over Daniel Koning’s map of the Española quadrangle and I noticed something I’d missed before, that some of the places I’d read as Qay1 were really Qayi.

Qay1 is his code for alliuvial soils laid down in the first phase of the post-glacier Holocene period. The river bottom is Qay2, a younger layer.

Qayi turns out to be some intermediate phase of sand and gravel bands, the very strata I’d noticed along some of the taller walls in the far arroyo. The same pattern appeared in the shallow walls of the great expanses of both arroyos. This is precisely where he’d marked Qayi on the map.

Some passing reference in Ted Galusha and John Blick’s article on Española sedimentation that I’ve slowly been reading sent me to look up the Otowi lava flows they said had dammed the Rio Grande in recent times.

I discovered Steven Reneau and David Dethier’s work on area lakes created when landslides dammed the Rio Grande around the Otowi bridge. One occurred around 43 thousand years ago and created a lake some 15.5 miles long that lasted anywhere from a hundred to a thousand years.

Another landslide created a pool 13 miles long about 17.5 thousand years ago which broke suddenly. The most recent, formed about 12.4 thousand years ago, was also about 15.5 miles long and filled completely with layers of sediment.

During much of this time, the very end of the Pleistocene, there was greater rainfall than now, so the river levels would have been higher. The most recent lake was 100' deep.

This area is well within 10 miles of the Otowi bridge, probably much closer if you’re a crow or a drop of water.

One small mystery has been solved, the origin of those gravel bands. What still is unknown is why the channels that are being opened now in the arroyos and washes were there to be filled by Qay1 and Qayi in the first place.

The Cone

This afternoon I went back to the cone, determined not to be fooled again by its wiles. This time I took the simple path, the one from the near wash. As I walked up the easy grade, I realized the cone might just be the tip of the hill I live on, the one that had caused so many water problems in the past.

As soon as I got close I saw that it wasn’t bare because of erosion caused by the ATV rider. It was actually stone and not some soft soil. Daniel Koning had said it was tertiary, not the more recent quaternary. The two were there to see on the slope where the grass couldn’t hold its own.

I started climbing the cone. The more I climbed, the more the top receded into a face of gravel.

I felt no overwhelming urge to make it to the top and yodel. My knees were chanting "Jack and Jill went up the hill." The view of the black mesa was quite spectacular where I stood.

On the way back down I picked up some pieces of the grey, rough textured stone for the Rock Queen.

Hopefully she can tell me what it really is, something more useful than tertiary side of the geological change.

Soot

This morning I walked to the far arroyo for the first time since Wednesday’s rain. Everywhere there were signs of the Las Conchas fire.

When I entered below the ranch road I saw black soot laying in water paths left on the bottom.

As I walked up stream I saw the charcoal trails along the low left banks. As I came back down, they were also on the right side, swirling along the base of the high walls.

I could only think it’s a Goldilocks situation. Earlier this summer, when water scoured the bottom of the arroyo, it was passing through so quickly it left little behind. Other times, the rain was so gentle it only moved silt a few feet. The traces of black were slight.

Wednesday it rain most of the day and much of the night, a gentle rain that soaked in. I’m guessing that it washed a layer of sand from the surface of those blocks I noticed earlier where it had accumulated and the soot and sand landed somewhere down stream.

Upstream, there must have been other patches of ash waiting to move. Each time this year when some dark dust moved from higher up the arroyo, it replaced some that had been washed down stream. Perhaps it had slowly become concentrated in areas near the main water paths. Finally, there was enough rain to collect it and move it slowly where it could drop between Wednesday’s showers.

The fire was suddenly visible everywhere again.

The Wash

A bare cone stands back from the road, beckoning you to come discover. It’s sides have already been marred by ATV drivers who took the challenge. Yesterday, I heeded its siren call.

I was coming back from the near arroyo when I thought I spied a path to its base, a sort of gently sloping, lowland route. It had the right come hither look, a promise it wouldn’t be hard on the knees.

I started back. The grass covering disappeared to expose the usual tan sand and clay.

Then the bared ground turned into a dry arroyo, a wash completely hidden from the road.

The wash turned into a maze of washes that might somehow, if I followed the right one, lead me back to the arroyo.

The cone became harder and harder to approach.

I turned and found the wash also connected to one that crosses the county road close to my house. I chickened out and took the low road home.

The Near Arroyo

The near arroyo shows the marks of man even more than the far one.

The road goes over, rather than through it. The local acequia dumps on the river side of the bridge, digging a hole where the water falls. As a result, the one side of the arroyo is more than twice as deep as the other.

Even when it’s not running, the open sections of the ditch that runs back to the Santa Cruz river collect rain water. After Wednesday’s rain, the point where it falls could be seen in the shelf of sand it carved in the bottom.

Three large culverts carry water under the road. They force the water into narrow channels which dig nearly a foot into the soft ground on the upriver side. In the summer, the heat dries the land and the wind smooths the edges, eventually carrying away much of the temporary island.

This arroyo, like the far one, has its sources three or four miles away in the Barrancos badlands that parallel highway 285 that runs from Pojoaque to Española. The rains bring down debris and weeds, especially Russian thistles, that are stopped by the culverts and sometimes block them.

While I think of the arroyo as having two sides, the deep one caused by the acequia and the swallow one carved by the culverts, both acts of man appear on both sides.

Last summer, a lateral was added to the acequia that now dumps just before the bridge on the upstream side. However, with this year’s drought, it hasn’t had a chance to run enough yet to have much impact.

And, on the other side of the bridge, the water leaves the culverts in narrow channels that dig their own paths, especially on the side away from where the acequia dumps. Apparently, the two paths of merge and push the water to the one side.

The erosion caused by the mere existence of the bridge also endangers it. Last year, the local ditch association had to replace the culverts with longer ones and rebuild the concrete faces. At that time, they also added the stone reinforcements.

Note: Top picture is looking towards the badlands on the other side of the Rio Grande and the Jemez. The brown legs in the second and fourth pictures belong to the flume that carries over the ditch water that eventually finds its way to the far arroyo.

The River Runs

Wednesday it rained, day and night.

Thursday noon when I went to the post office the river was running higher and faster, the color of caffè latte.

I thought, ah yes, of course, the river’s running. It rained. I didn’t think, I’m seeing the great shaping force of this part of the country roused from a long seasonal slumber.

I didn’t connect even though I’d spent the morning looking at Daniel Koning’s “Preliminary Geologic Map of the Española 7.5-minute Quadrangle” which shows a lopped triangle with the Rio Grande and Route 285 on the sides, the Rio Pojoaque to the south and the Santa Cruz river on the north just above where I was driving over the Griego bridge.

He shows the road near my house skirts what he labels a “geological contact.” The soils to the river side have recent alluvial origins. The ones to the east date back to an earlier Tertiary period. Since the time before the great glaciers when the river began to connect the discrete basins of the rift valley, water has been digging and padding its channel.

It’s removed or redeposited the existing tertiary sediments, or perhaps both at the same or different times, and left a boundary area that needs no geologist to recognize.

I went back to today to the Griego Bridge to see the river at the point the Santa Cruz enters. The current was slower, but the water was still carrying dirt. Gravel and sand have been deposited where the dammed and controlled water flow of the one meets the less tamed Rio Grande.

Then I drove home and looked again at that “geological contact” out the car window. You could imagine the grass as some great sea lapping against dunes. And like ladies of a certain age who once were rivals and now nod when they meet, you can only guess their pasts from the differences in their outerwear, their vegetation.

Running Water

Another hurricane in the western Caribbean, some more rain this morning.

We’re past the danger point this year, when water is a potential enemy. In late summer, before the first rain after a long drought, you worry the ground has become too hard to absorb water and it will run off the surface. Firefighters were especially concerned about Santa Clara canyon where heat from the Las Conchas fire had baked the soil.

When I first moved here, I could be flooded when water coming off the hill turned into a rolling sheet that gathered force as it moved, fed as it was, every inch, by more rain. Water poured through the joints in my the rail tie retaining wall, until I stuffed broken tiles behind the cracks.

My uphill neighbor had worse problems. He’d built his house in an abandoned road bed which channeled the water his way. A few years ago, he got a backhoe and built a bunker behind his property which diverted the flow of water enough that I was no longer in its path.

At the corner of my property, the paved road makes a sweeping turn. People who live downhill regularly had their garages flooded as water running down the road, swollen by feeds from every driveway uphill, flowed down their drives. One year, a number also had their well houses inundated.

The curve is actually an intersection of three roads - or so the people who numbered the roads believe. The compacted dirt ranch road, which branches from the curve, also collects water from the paved road and sends it along the side of my property.

From there it flows towards the arroyo, collecting water from every break in its banks made by an ATV. This summer I could see where the water had penetrated from the surface, and where it has also been absorbed at the base, with a dry band between the two zones.

The ranch road continues on the other side, which means it feeds water into the arroyo from both sides.

I’m beginning to think one reason the arroyo is as wide as it is in that area is that the load of water has washed away more of the banks downstream. Since the water from the road would turn as soon as possible, it would move along the walls while the water coming from upstream would continue its path somewhere in the center.

Chamisa has taken advantage of the different flow rates to colonize the dryer areas between the banks. This has created the widened arroyo composed of platforms at the edges with some vegetation that drop into obvious water channels that move along two sides of islands anchored by chamisa.

Pictures
1. Ranch road going through the arroyo, 10/20, from top of the left bank; ATV tracks enter the arroyo on both sides of the curving road; my house is the one with the gray-white roof.
2. Water running down hill between dead grasses on the west side of my house to drain into the ranch road, 8/21.
3. Hill behind my uphill neighbor’s house which is elevated on the right by the abandoned road bed marked by the fence posts. The berm runs parallel to the house.
4. Bank of ranch road, 8/2.
5. Arroyo bottom, 9/11, from the platform at the base of the right bank.

Arroyo Walls

Appearances are deceiving.

When you walk through the far arroyo, the walls on the one side are tall and furrowed like the sandstone you see in pictures of Egypt’s Valley of the Kings. On the other side are low, sloping banks.

You assume the first are more substantial than the second. Don’t bet your climbing knees on it.

The surface here is the ungainly named Santa Fe Conglomerate, a lamination of sand, clay, and gravel. If you paw at the sand-clay layers they crumble in your fingers. If you claw at the gravel it stays put until you increase your pressure.

The sculptured surfaces of the tall walls must be the result of constant wind action. When it falls, the rain pocks the skin, leaving small depressions. This year, soot from the Las Conchas fire collected on the ridges between.

The slovenly surfaces of the other result from rain which forms a glaze that resists the wind. When it washes out, however, it disintegrates faster than the clay it lay with. And, apparently when its surfaces can’t produce an adhesive, it leaches and, eventually, brings the clay down with it.

Ditch Head

Today I went searching for the ditch head that feeds into the far arroyo. Head may not be the right word for the boundary between man and nature, but it’s all I can think of for the terminus.

A concrete lined ditch sweeps across the land between the near and far arroyos, going underground where it nears a road.

When it reaches the last piece of land, a neck of concrete, so thin it resembles plaster, channels the water away from the owner’s coyote fence.

It’s path from there is obvious, its course marked this time of year by brilliant leaf colors. There’s a long drop into a dry pool where water collects briefly.

What’s interesting is that after the drop the water’s route is no longer directed by the actions of humans, but follows ancient soil patterns.

The area lies on a long downward slope that angles south and west. The surface is crossed by ridges and valleys going roughly east-west. When nothing has disturbed the land, all’s covered with bunch grass.

When a low place is created in the land, perhaps by a road cut or ATV tires, water has a new path. The softer soils absorb more of the water than the harder ones. They are dissolved from the developing walls, fall into the bottom, and are carried away by wind or water.

The harder soils stay longer, creating what look like eroded craters.

The acequia water, which runs most of the summer, apparently lapped into soft spots of soil along its course that then began washing out. There are two major gullies uphill from the main water path. As they near each other and the main ditch path, they remain separated from each other by harder land.

The harder land looks much like the hard walls in the arroyo, and like those it doesn’t support as much vegetation as the softer soils that are eroding away.

The thing that has always surprised me about this man-made feeder to the arroyo is that it ends so abruptly that it endangers the houses near it. It’s hard to tell without digging before you build if a particular section of land here is on hard ground or soft.

The acequia association probably had no choice. After years of land disputes, and I suspect these particular houses, as well as mine, are sitting on some land grab, the pueblo probably wasn’t interested in making any more of its land attractive to interlopers and simply said no.

Unfortunately, no is not a word water understands.

Pictures top to bottom: 1 - ditch just outside the last fence. 2 - ditch as seen through the last fence. 3 - ditch from bottom looking up at same fence. 4 - land from across the ranch road; the white shed left of center is next to the arroyo terminus. 5 - the current end of one of the wash outs feeding into the ditch path. 6 - two wash outs separated by a spit of land; the cottonwoods to the right mark the main ditch path. 7- wash out between #5 and #6 showing bare hard rock and colonized softer soil.

The Far Arroyo

I live between two arroyos, each about a quarter mile from the house. The one to the north I think of as the near arroyo because I cross it every time I drive into town. The other, to the south, I think of as the far arroyo because I have to walk across pueblo land to get to it.

The far arroyo changes its character every fifty or a hundred feet, partly because of humans. At the time the USGS map was revised for this quadrangle, the local ditch emptied into the near arroyo.

At some later time, a pipe was installed to carry water across the arroyo and out to the land downhill from me. A neighbor told me the land under his house and mine were once part of a ranch, perhaps the same one that survives beyond the arroyo. The acequia extension dumps as soon as it reaches pueblo ground.

The water has cut its own path to the far arroyo. From a distance it can be followed by the trees that grow along the banks, including those yellow cottonwoods pictured in the previous entry. The above picture was taken from the arroyo at the point where the acequia water is heading its way.

Thursday I walked down the arroyo to the point where the acequia feeder enters the arroyo. At that point the water has cut a path not much more than a foot deep.

The water flows immediately to the right where it has cut through the soft bottom land. The sand and clay wash away, leaving a path of gravel, the generic Santa Fe Conglomerate that covered this area before the rift opened.

The soft soil absorbs water from both the air and the arroyo, which makes it more likely to crumble. The water band hasn't quite evaporated in the picture below.

The water apparently eats back through the soft soil under harder upper layers, until they collapse from lack of support. The water line under the rock can be traced by the appearance of Russian thistles that find enough sustenance to germinate in late summer on the downfall that flares from the bottom.

The arroyo widens and deepens where some previous geological event created the layers of hard rock.

Then, when the hard rock ends, the wall abruptly stops and the arroyo returns to bottomland vegetation.

That’s the point I turned back Thursday.